This disclosure relates generally to image processing techniques. More particularly, but not by way of limitation, it relates to novel techniques for performing image defringing, as well as red color channel and blue color channel reconstruction from a variety of color filter arrays (CFAs).
In photography, particularly RAW images, different artifacts can affect the quality of the edges of objects in the image. This effect is more noticeable when the edge has high contrast. In repairing such a color “fringe” region, it is often effective to merely diminish the noticeability of the fringe. This can be done through chroma replacement with nearby values, desaturation, and by other means.
Usual approaches to defringing involve chroma blur and chroma median filtering, which are operations that apply to the whole image. One motivation for improving upon these usual approaches is the understanding that, typically, not all pixels of an image display color fringing. Usually, fringing only occurs in high-contrast edges. Mere masking of the effects of the whole-image operations can improve the result, but further improvements are still possible. Further improvements are also possible to the process of reconstructing red and blue color channel information for CFAs, as typical demosaicing techniques may themselves introduce additional color fringing artifacts to the image.